Parking lock for a vehicle comprising a spreadable locking element

Abstract

The invention relates to a parking lock (12, 26) for a vehicle (34), comprising a parking lock gear (13) which is mounted on a drive shaft (36) for transmitting a torque to a drive wheel of the vehicle (34), the parking lock gear (13) having teeth (14) which are mutually spaced and between which there are tooth gaps (15), and a locking pawl (16, 28) which has a locking element and can be moved to a parking position in which the locking element engages in a tooth gap (15) in the parking lock gear (13), the locking element being spreadable in the circumferential direction of the parking lock gear (13) in the parking position, so that the locking element bears against both of the teeth (14) delimiting the tooth gap (15) and blocks rotation of the parking lock gear (13) about the rotation axis of the drive shaft (36). The invention also describes a vehicle (34) having a parking lock (12, 26) and a method for operating the parking lock.

Description

[0001] Parking lock for a vehicle with a spreadable locking element

[0002] The invention relates to a parking lock for a vehicle, comprising a parking lock wheel which is mounted on a drive shaft for transmitting a torque to a drive wheel of the vehicle, wherein the parking lock wheel has spaced-apart teeth between which there are tooth gaps, and a pawl with a locking element which can be moved into a parking position in which the locking element engages in a tooth gap of the parking lock wheel.

[0003] In a parking lock described in DE 10 2019 128 601 A1, a pawl has an angled end that can be moved into a tooth gap to prevent movement of the parking lock wheel. The size of the tooth gaps of the parking lock wheel and the length of the angled end of the pawl are matched so that there is play between the tooth gap and the angled end of the pawl in the parked position.

[0004] An electric motor or electric machine in a vehicle can be used to drive one of the vehicle's wheels. The electric motor and its associated power electronics can be operated in a charging mode to transform the supplied charging voltage when charging a traction battery, for example, doubling it from 400 V to 800 V (DC boost charging). In this charging mode, the stator windings of the electric motor are subjected to transient currents, which can cause the rotor to move or vibrate unintentionally. Because the rotor is connected to a drive wheel of the vehicle via a drive shaft, the vehicle itself can also move or vibrate unintentionally.

[0005] The invention is based on the objective of providing a parking lock for a vehicle that prevents unwanted movements and vibrations of the vehicle during DC boost charging. To achieve this objective, a parking lock with the features of claim 1 is provided.

[0006] In the parking lock according to the invention, the locking element in the parking position can be spread in the circumferential direction of the parking lock wheel, so that the locking element rests against both teeth that define the tooth gap and blocks rotation of the parking lock wheel about the axis of rotation of the drive shaft. This prevents unwanted rotation of a drive wheel of the vehicle, which would result in unwanted movement or vibration of the vehicle during DC boost charging.

[0007] By moving the pawl into the park position, the parking pawl wheel is only locked to the extent that it can still rotate a small angle around the axis of rotation of the drive shaft. The additional spreading of the spreading element completely prevents or blocks the rotation of the parking pawl wheel around the axis of rotation. The spread locking element can, for example, rest against the tooth flanks of the two teeth that define the tooth gap.

[0008] A further development of the invention provides that the parking lock has a push rod which can be moved into a first position, whereby the locking pawl is moved into the park position, and from the first position into a second position, whereby the locking element is spread apart. The movement of the push rod can occur, among other things, along its longitudinal axis. The push rod can, for example, be moved from a release position, in which the parking lock wheel is not locked, into the first position.

[0009] It can also be provided that the locking element of the parking lock according to the invention has a locking pin rigidly connected to the pawl and an expanding pin movably connected to the pawl, wherein the locking element is expanded by moving the expanding pin away from the locking pin. Preferably, the expanding occurs automatically when the pawl is moved by means of the push rod. In this state, both the expanding pin and the locking pin bear against the two teeth that define the tooth gap of the parking lock wheel, so that the parking lock wheel is mechanically blocked.

[0010] The pawl can have a lever that is rotatable with the push rod about a pivot point located on the pawl when the push rod is moved from the first position to the second position, thereby moving the spreading pin away from the locking pin. In such a design, the lever rotates automatically when the push rod is moved, pressing the spreading pin against a tooth of the parking lock wheel.

[0011] According to the invention, it is preferred that a torsion spring is arranged on the lever. The torsion spring is tensioned when the lever is rotated by the push rod. Under the influence of the energy stored in the torsion spring, the lever is rotated back to its starting position when the push rod is moved from the second position to the first position. The locking of the parking lock wheel by the spreading pin is thereby released.

[0012] Within the scope of the invention, it can also be provided that the locking element has two expanding jaws movably connected to the pawl and is expanded by moving or rotating the expanding jaws away from each other. When the pawl is in the second position, the two expanding jaws bear against teeth of the parking lock wheel, for example against their tooth flanks, and block rotation of the parking lock wheel.

[0013] In this context, the pawl may be designed to have an expanding wedge that can be moved between the expanding jaws by the push rod when the push rod is moved from the first position to the second position, thereby moving the expanding jaws away from each other. As the push rod moves into the second position, the expanding wedge spreads the two expanding jaws so that they rest against both teeth of the parking pawl that define the tooth gap. This prevents unwanted movement or rotation of the parking pawl and the drive wheel connected to it via the drive shaft.

[0014] Within the scope of the invention, the spreading jaws can be rotatably attached to the pawl. Likewise, the spreading wedge can be rotatably attached to the pawl. This rotatable attachment enables automatic alignment of the spreading jaws and the spreading wedge, ensuring that the spreading jaws or the spreading wedge come into contact with the teeth of the parking lock wheel (especially their tooth flanks) in a flat, contact position.

[0015] Preferably, a spring is arranged on the expanding wedge to return it to its original position when the push rod is moved from the second position to the first position. When the push rod moves from the first to the second position, the spring is tensioned. Under the influence of the energy stored in the tensioned spring, the expanding wedge automatically returns to its initial position when the push rod is moved back.

[0016] In addition, the invention relates to a vehicle with a parking lock of the type described and an electric motor for generating the torque, wherein the electric motor has a stator with stator windings configured for DC boost charging of a battery.

[0017] The invention also relates to a method for operating a parking lock of the type described, comprising the following steps: moving the pawl into the park position so that the locking element engages in the tooth gap, and spreading the locking element in the park position circumferentially around the parking lock wheel so that the locking element rests against both teeth bounding the tooth gap and blocks rotation of the parking lock wheel about the axis of rotation of the drive shaft. The invention is explained below with reference to exemplary embodiments and the drawings. The drawings are schematic representations and show:

[0018] Fig. 1 shows a conventional parking lock in a release position;

[0019] Fig. 2 shows an embodiment of a parking lock according to the invention, which is in a parking position;

[0020] Fig. 3 shows a further embodiment of a parking lock according to the invention, which is in a release position; and

[0021] Fig. 4 shows a vehicle according to the invention with a parking lock according to the invention.

[0022] Fig. 1 shows a conventional parking lock 1 of a vehicle, with a parking lock wheel 2 mounted on a drive shaft 3. The drive shaft 3 serves to transmit torque to a drive wheel of the vehicle. The parking lock wheel 2 has spaced-apart teeth 4, between which there are tooth gaps 5. The parking lock 1 shown in Fig. 1 is in a release position in which the drive shaft 3 is rotatable.

[0023] The parking lock 1 further comprises a pawl 6 with a locking element designed as a locking pin 7. The pawl 6 has a through-hole 8 about which it is rotatably mounted. The through-hole 8 defines the axis of rotation of the pawl 6. At the opposite end of the pawl 6 is a push rod 9, which is movable, at least approximately, in its longitudinal direction. The movement can be effected by an electric drive, an electric actuator, or manually. At the free end of the push rod 9 is a driver 10, which contacts the outer contour 1 1 of the pawl 6. When the push rod 9 is extended from the release position shown in Fig. 1, i.e. upwards in the view of Fig. 1, the pawl 6 is rotated counterclockwise around the through opening 8, which serves as the axis of rotation, by the driver 10, which rests against the outer contour 1 1 of the pawl.By rotating the pawl 6, the locking pin 7 is engaged in a tooth gap 5 between two adjacent teeth 4. In this parked position, the parking lock wheel 2 is locked, thus preventing movement of the drive shaft 3 and the associated drive wheel of the vehicle.

[0024] Charging stations for electric vehicle batteries often provide a charging voltage of 400 V. However, some electric vehicles require a charging voltage of 800 V. For this, the available charging voltage of 400 V is transformed to 800 V by the electric motor and its coupled inverter. This requires active modulation of the stator currents. It must be ensured that no movement of the electric motor's rotor occurs, which could otherwise lead to undesirable vibrations or movements of the vehicle body or the entire vehicle. With the conventional parking lock 1 shown in Fig. 1, such vibrations or movements can occur because there is play between the tooth gap 5 and the locking pin 7 in the parked position.

[0025] Fig. 2 shows a detail of a modified parking lock 12, which, in accordance with the conventional parking lock of Fig. 1, has a parking lock wheel 13 with teeth 14 and tooth gaps 15. The parking lock 12 is shown in the park position in Fig. 2. A pawl 16 has the fixed locking pin 17, which is located in the tooth gap 15. The driver 18, connected to a push rod (not shown), contacts the outer contour of the pawl 16. When the push rod is moved from the release position to the first position (park position), the driver 18 pushes the pawl 16 into the tooth gap 15, as shown in Fig. 2. In addition to the fixed locking pin, the pawl 16 has an expanding pin 19. The expanding pin 19 is arranged at one end of a two-armed lever 20, which is rotatably mounted on the pawl 16. The driver 18, connected to the push rod, has a projection 21.When the push rod is moved beyond the first position into a second position, the lever 20 is rotated about its axis of rotation. The other end of the lever 20 then presses the associated expanding pin 19 with its outer surface 23 against an inner surface 24 of the tooth gap 15. In this state, the locking element, comprising the fixed locking pin 17 and the movable expanding pin 19, is clamped in the tooth gap 15. This two-sided clamping prevents any vibrations or movements of the parking lock wheel 13 and thus also any rotation of the drive shaft coupled to the parking lock wheel 13.

[0026] The push rod can be moved into a first position by sliding it along its longitudinal axis, in which the pawl 16 is brought into the park position. By further sliding the push rod along its longitudinal axis in the same direction, the locking element is spread apart by moving the spreading pin 19 away from the locking pin 17. Fig. 2 shows the parking lock 12 in this second position.

[0027] The lever 20 is equipped with a torsion spring 25. The torsion spring 25 is tensioned when the lever 20 is rotated by the projection 21 of the driver 18. To release the parking position, the push rod is first retracted from the second position to the first position. When the projection 21 is retracted and no longer presses against the end of the lever 20, the torsion spring 25 rotates the lever 20 back to its initial position by means of the energy stored in the torsion spring 25. The expanding pin 19 is then still located in the tooth gap 15, but it no longer rests flat against the inner surface 24 of the tooth gap 15. However, rotation of the parking lock wheel 13 remains blocked. When the push rod is pulled further back from the first position into the release position, the pawl 16 pivots about its axis of rotation, thereby moving the locking pin 17 and the expanding pin 19 out of the tooth gap 15.In this release position, the parking lock wheel 13 is no longer locked and the drive shaft on which the parking lock wheel 13 is located can be rotated freely.

[0028] Fig. 3 shows another embodiment of a parking lock 26 with the parking lock wheel 12, which has teeth 14 and tooth gaps 15. A substantially linearly movable push rod 27 interacts with a pawl 28, which is rotatably mounted about a through-opening 29. The pawl 28 comprises a locking element having two expanding jaws 30, 31 rotatably connected to the pawl. In addition, a rotatably mounted expanding wedge 32 is provided on the pawl 28.

[0029] When the push rod 27 is extended, the pawl 28 is moved from the release position shown in Fig. 3 to the first position. The push rod

[0030] 27 presses against the outer contour of the pawl 28, so that the pawl

[0031] 28 is rotated clockwise until the spreading jaws 30, 31 are inserted into a tooth gap 15.

[0032] When the push rod 27 is extended from this first position to the second position, it presses against a section of the rotatably mounted spreading wedge 32. This causes the spreading wedge 32 to rotate about its axis of rotation 33. The push rod 27 presses the spreading wedge 32 between the bearing points of the spreading jaws 30, 31. The outer surfaces of the spreading wedge 32 are in contact, at least approximately, with the opposing surfaces of the spreading jaws 30, 31. The spreading wedge 32 rotates the spreading jaws 30, 31, moves them away from each other, and spreads them apart. With their outer surfaces, the spreading jaws 30, 31 then rest against the two teeth 14 that define the tooth gap 15 and block rotation of the parking lock wheel 13. Fig. 4 shows a vehicle 34 with an electric motor 35, which is connected to a drive shaft 36 for driving an axle of the vehicle 34. A parking lock wheel is located on the drive shaft 36 as part of a schematically represented parking lock 12.

[0033] Reference symbol list

[0034] 1 parking barrier

[0035] 2 parking lock wheel

[0036] 3 Drive shaft

[0037] 4 teeth

[0038] 5 tooth gap

[0039] 6 locking pawl

[0040] 7 locking pins

[0041] 8 Through opening

[0042] 9 Push rod

[0043] 10 drivers

[0044] 11 Outer contour

[0045] 12 Parking restrictions

[0046] 13 Parking lock wheel

[0047] 14 teeth

[0048] 15 tooth gaps

[0049] 16 Locking pawl

[0050] 17 locking pins

[0051] 18 drivers

[0052] 19 expansion pins

[0053] 20 levers

[0054] 21 lead

[0055] 22 axis of rotation

[0056] 23 outdoor area

[0057] 24 Inner surface torsion spring

[0058] Parking closure

[0059] Push rod

[0060] Locking pawl, through opening, spreading jaw

[0061] Spreader jaw

[0062] Spreader wedge

[0063] axis of rotation

[0064] vehicle

[0065] electric motor

[0066] drive shaft

Claims

Patent claims 1. Parking barrier (12, 26) for a vehicle (34), comprising: - a parking lock wheel (13) mounted on a drive shaft (36) for transmitting a torque to a drive wheel of the vehicle (34), wherein the parking lock wheel (13) has spaced-apart teeth (14) between which tooth gaps (15) are located, - a pawl (16, 28) with a locking element which can be moved into a park position in which the locking element engages in a tooth gap (15) of the parking lock wheel (13), characterized in that the locking element in the park position can be spread in the circumferential direction of the parking lock wheel (13) so that the locking element rests against both teeth (14) limiting the tooth gap (15) and blocks a rotation of the parking lock wheel (13) about the axis of rotation of the drive shaft (36).

2. Parking lock according to claim 1, comprising a push rod (27) which is movable into a first position, wherein the locking pawl (16, 28) is moved into the parking position, and is movable from the first position into a second position, wherein the locking element is spread.

3. Parking lock according to claim 2, wherein the locking element has a locking pin (17) rigidly connected to the locking pawl (16) and a spreading pin (19) movably connected to the locking pawl (16), wherein the locking element is spread by moving the spreading pin (19) away from the locking pin (17).

4. Parking lock according to claim 3, wherein the locking pawl (16) has a lever (20) which is rotatable with the push rod (27) about a pivot point (22) arranged on the locking pawl (16) when the push rod (27) is moved from the first position to the second position, whereby the spreading pin (19) is moved away from the locking pin (17).

5. Parking lock according to claim 4, wherein a torsion spring (25) is arranged on the lever (20) for turning the lever (20) back when the push rod (27) is moved from the second position to the first position.

6. Parking lock according to claim 2, wherein the locking element has two spreading jaws (30, 31) movably connected to the locking pawl (28) and is spread by moving the spreading jaws (30, 31) away from each other.

7. Parking lock according to claim 6, wherein the locking pawl (28) has a spreading wedge (32) which is movable by the push rod (27) between the spreading jaws (30, 31) when the push rod (27) is moved from the first position to the second position, whereby the spreading jaws (30, 31) are moved away from each other.

8. Parking lock according to claim 7, wherein the spreading jaws (30, 31) and / or the spreading wedge (32) are rotatably attached to the locking pawl (28).

9. Parking lock according to claim 7 or 8, wherein a spring is arranged on the spreading wedge (32) for moving the spreading wedge (32) back when the push rod (27) is moved from the second position to the first position.

10. Vehicle (34) with a parking lock (12, 26) according to one of the preceding claims and an electric motor (35) for generating the torque, which has a stator with stator windings configured for DC boost charging of a battery.

11. Method for operating a parking barrier (12, 26) according to one of claims 1 to 9, comprising the steps - Moving the pawl (16, 28) into the park position so that the locking element engages in the tooth gap (15), and - Spreading the locking element in the parking position in the circumferential direction of the parking lock wheel (13), so that the locking element rests against both teeth (14) limiting the tooth gap (15) and blocks rotation of the parking lock wheel (13) around the axis of rotation of the drive shaft (36).

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